This disclosure relates to sensors for detecting very high temperatures. It is specifically directed to devices for continuously measuring temperature in the range of 1,000 to 2,000 K., which might occur during operation or testing of nuclear or fusion reactors.
This invention arose from tests requiring a direct indication of temperature within nuclear reactors. It meets instrumentation requirements for control room indication of very high temperatures needed in the monitoring of operational parameters to protect against damaging fuel rod conditions that might otherwise remain undetected.
The present invention arose in response to a need for direct continuous measurement of temperatures higher than can be monitored by existing immersion devices. The highest temperatures which can be measured by an immersion device today is between 1700 to 1800 K. (1427.degree. to 1527.degree. C.). Even these measurements can only be accomplished by use of extremely expensive tungsten-rhenium thermocouples. Current scientific research relating to fusion reactions and other test efforts relating to nuclear reactors and monitoring of loss of coolant accidents have intensified the need to directly monitor higher and higher temperatures. The present invention provides a relatively inexpensive device for accurately measuring these temperatures in a direct fashion.
The present device consists of two electrical conductors separated by a mass of electrical insulating material having a measurable resistivity change in relation to its temperature within the high temperature range to be monitored. By monitoring the electrical resistance across the conductors through the mass of insulation material, one can be provided with a direct reading of temperature changes in a very high range of temperatures.